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001 General Warnings and Cautions
PLEASE READ THESE WARNINGS AND CAUTIONS
BEFORE PROCEEDING
WITH MAINTENANCE AND REPAIR WORK.
WARNINGS-
See also CAUTIONS
- Some repairs may be beyond your capability. If you lack the skills, - Catch draining fuel, oil, or brake fluid in suitable containers. Do
tools and equipment, or a suitable workplace for any procedure
not use
foodor beverage containers that might mislead someone
described in this manual, we suggest you leave such repairs to
into
drinking from them. Store flammable fluids away from fire
an authorized BMW dealer service department or other qualified
hazards. Wipe up spills at once, but do not store the oily rags,
shop. which can ignite and burn spontaneously.
. Do not reuse any fasteners that are worn or deformed. Many fas- Always observe good worRshop practices. Wear qoqqles when
teners are designed to be used only once and become
unreliable you operate machine tools or work with battery acid:kloves or
and mav fail when used a second time. This includes, but is not other
~rotective clothino should be worn whenever the iob re-
limited io, nuts, bolts, washers, self-locking nuts or bolts, clrclips yires' working with harmful substances.
and cotter pins. Always replace these fasteners with new parts.
Greases, lubricants and other automotive chemicals contain toxic
. Never work under a lifted car unless it is solidly supported on
substances, many of which are absorbed directly through the
stands
desiqned for the purpose. Do not supeort a car on cinder
skin. Read the manufacturer's instructions and warninos careful-
blochs, hollow tiles orotherbrops that may drurnbie undercontin-
uous toad. Never work under a car that is supported solely by a
iack. Never work under the car
while the enqine is runninq. - -
If you aregoing to work underacaron the ground, makesure that
the ground is level. Block the wheels to
keep the car from rolling.
Disconnect the battery negative
(-) terminal to prevent others
from starting the car while you are under it.
- Never run the engine unless the work area is well ventilated. Car-
bon monoxide kills.
Rings, bracelets and other jewelry should be removed so that
they cannot cause electrical shorts, get caught in running ma-
chinery, or be crushed by heavy parts.
- Tie long hair behind your head. Do not wear a necktie, a scarf.
loose clothing, or a necklace when you work near machine tools
or running engines. if your hair, clothing, or jewelry were to get
caught in the machinery, severe injury could result.
DO not attempt to
work on your car if you do not feel well. You in-
crease the
danger of injuryto yourseliand others if you are tired,
uDset or have taken medication or anv other substance that mav
keep you from being fully alert.
Illuminate your work area adequately but safely. Use a portable
iy. Use hand and eye protection. Avoid direct skin conGct.
Disconnect the battery negative (-) terminal whenever you work
on the fuel system
orthe electrical system. Do not smokeorwork
near heaters or other fire hazards. Keep an approved fire extin-
guisher handy.
. Friction materials (such as brake pads or shoes or clutch discs)
contain asbestos fibers or other friction materials. Do not create
dust by grinding, sanding, or by cleaning with compressed air.
Avoid breathing dust. Breathing any
friclion material dust can
lead to serious diseases and may result in death.
Batteries
giveoff explosive hydrogen gas during charging. Keep
sparks, lighted matches and open flame away from the top of the
battery. If hydrogen gas escaping from the cap vents is ignited, it
will ignite gas trapped in the cells and cause the battery to ex-
plode.
Connect and disconnect battery cables, jumper cables or a bat-
tery charger only wilh the ignition switched off. Do not disconnect
the battery while the engine is running.
Do not quick-charge the battery (for boost starting) for longer
than one minute. Wait at least one minute before boosting the
battery a second time.
. . safety lighiforworking lnsideor under the car. Make sure the bulb - Do not allow battery charging vollage to exceed 16.5 volts. If the
is enclosed bv a wire caoe. The hot filament of an accidentallv
batten! beoins ~roducina oas or boilino violentiv, reduce the
broken bulb can ignite spilled
fuel, vapors or oil. , - - - charglng rate. ~oostlng a sutfaled battery at a igh charging rate
can cause an
explosion.
-
Continued on next page
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. .- . --
Lr -- - - - -- Cylinder Head Removal and Installation I -
- Release pressure at compression gauge valve, then remove
gauge from spark plug hole. Repeat test for each cylinder
and compare results with values given in Table a.
Table a. Compression testing specifications
Minimum compression
6-cylinder
10-1 1 bar (142-156 psi)
V-8 12-14 bar (174-203 psi)
Maximum difference between
cylinders (all engines)
0.5 bar (7 psi)
- Compression readings may be interpreted as follows:
Low compression indicates a poorly sealed combustion
chamber.
0 Relatively even pressures that are below specification nor-
mally indicate worn piston rings
andlor cylinder walls.
Erratic values tend to indicate valve leakage.
Dramatic differences between cylinders are often a sign of
a failed head
gasket, burned valve, or broken piston ring.
- If readings are within specifications, reinstall spark plugs and
ignition coils.
NOTE-
Used spark plugs should be reinstalled in the same cylinder
from which they were removed.
Tightening torque Spark plug to cylinder head 25 Nm
(18 ft-lb)
lanition coils to cylinder head 10 Nm (7.5 ft-lb)
- Remainder of installation is reverse of removal. Be sure to re-
install all wires disconnected during test, especially ground
wires at coils and cylinder head cover (where applicable).
Wet compression test
To further help analyze the source of poorcompression,awet
compression test is the next step.
- Repeat compression test, this time squirt a teaspoon of oil
into each cylinder. The oil will temporarily help seal between
piston rings and cylinder wall, practically eliminating leakage
past rings for a short time.
- If this test yields a higher reading than "dry" compression
test, there is probably leakage between piston rings and
cylinder walls, due either to wear or to broken piston rings.
- Little or no change in compression reading indicates other
leakage, probably from valves.
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-
Cylinder Head Removal and Installation c
q Remove secondary air inject~on check valve (arrow).
4 Remove cylinder head top cover:
Remove plastic trim caps (arrows).
Remove engine oil filler cap.
Remove cover hold down fasteners and lift off cover.
4 Remove ignition coils:
Disconnect ignition coil harness connectors.
. Remove coil mounting fasteners.
Remove coils.
Remove ground straps.
NOTE-
Make note of ground wire at mounting studs arrangement
during removal.
- Remove sparlc plugs.
- Remove cylinder head cover mounting fasteners and remove
cylinder head cover.
NOTE-
The cylinder head cover mounting bolt insulators and gas-
lets should be reinstalled in their original locations. Make
note of their arrangement during removal.
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Cylinder Head Removal and Installation
4 If applicable, remove secondary air injection pump:
Disconnect hose at one-way valve
(A).
Remove bolts at support bracket on strut tower (arrows).
Disconnect electrical harness from bottom of secondary
air injection pump.
Remove mounting bracket from strut tower.
4 Remove ignition coils:
* Disconnect ignition coil harness connectors.
Remove coil mounting fasteners.
Remove coils.
* Remove ground straps.
CA UTIOI\C
Note location of all ground wires. Failure to reinstall grounds
can result in permanent damage to engine control module or
ignition system components.
Set coil harness to side of engine compartment
- Remove cylinder head cover mounting fasteners and remove
cylinder head cover.
NOTE-
The cylinder head cover mounting bolt insulators and gas-
ltets should be reinstalled in their original locations. Male
note of their arrangement during removal.
- Remove spark plugs
4 Remove oil baffle cover from above intake camshaft.
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/Cylinder Head Removal and Installation
- Remainder of installation is reverse of removal, noting the fol-
lowing:
Use new gaskets when mounting intake
manifold. Tighten
nuts finger tight first, then torque to specification in stages
working diagonally from center out.
Be sure to reinstall ignition coil ground straps at cylinders
no.
3 and no. 7. See 120 Ignition System.
Reinstall cooling fan and shroud. See
170 Radiator and
Cooling System.
Refill and bleed cooling system as described in
170 Radi-
ator and Cooling System.
Change engine oil and filter as described in
020 Mainte-
nance.
CA UTIOG
To prevent damaging engine electricalsystems, be sure to in-
stall all ground wires previously removed.
Tightening torques
Camshaft sprocket to camshaft 15
Nm (11 H-lb)
Coolant manifold to cylinder head 10 Nm (7.5 H-lb)
Cylinder head cover nuts 10 Nm (7.5 ft-lb)
Exhaust manifold to head 22 Nm (17 ft-lb)
Engine mounts to subirame 42 Nm (30 ft-lb)
Spark plugs to cylinder head 22 Nm (17 ft-lb)
Right cylinder head, removing, M62 engine
- Remove left side exhaust manifold. See 180 Exhaust Sys-
tem.
- Remove intake manifold. See Intake manifold, removal
and installation,
M62 engine.
- Drain engine coolant. See 170 Radiator and Cooling Sys-
tem.
WARNING-
Use extreme caution when draining and disposing of engine
coolant.
Coolanl is poisonous andlellial lo liumans andpels.
Pets are
altracled to coolant because of 11s sfieet smell and
fasle. Seelc medcal anenfion immed~alely if coolant is ingesl-
. .-
< Remove engine coolant manlold mo~nlng fasreners and
carei~lly remove manifo d.
. I
NOTE
Engine 8s slioivn removed lor clarify
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11 6-9
Cvlinder Head and valvetrain1
4 Remove ignition coils and spark plugs.
V-8 models: remove mounting nuts (arrows) from wiring har-
ness ducting.
< V-8 models: disconnect fuel injector electrical connectors
from injectors:
Pry one corner of wire
loclc clip (arrow) on first injector.
Repeat for all injectors.
Lift wire ducts off and set aside.
- V-8 models: disconnect battery jump start post terminal from
left cylinder head cover.
- 6-cylinder models: remove oil filler cap and unclip vent con-
nection from cylinder head cover.
- Remove cylinder head cover mounting fasteners and re-
move cylinder head cover(~).
NOTE-
The cylinder head cover mounting bolt insulators and gas-
Icets should be reinstalled in their original locations. Make
note of their arrangement
during removal.
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I Cylinder Head and Valvetrain
- Remove adjustable primary timing chain tensioner tool and
reinstall primary chain tensioner cylinder to cylinder head.
Tightening torque
Primary chain tensioner cylinder
to 70 Nm (52 ft-lb)
cylinder head
- Remove flywheel locking tool from crankcase. Replace spe-
cial tool bore sealing plug.
- Remove camshaft locking tools from cylinder head
Install intake camshaft cover and cylinder head cover.
Check for correct seating of half-moon seals (A) in back of
cylinder head cover.
Use a small amount of Three Bond
8 1209 or equivalent
sealing compound at corners
(B) of half-moon cutouts.
Seat gasket and seal corners at VANOS unit with Three
Bond
@ 1209.
Tightening torque Cylinder head cover to cylinder head
(M6) 10 Nm (89 in-lb)
- Installation of the remaininq parts is reverse or removal, not- -
ing the following:
Change engine
011 and f~lter as descr~bed in 020 Mainte-
nance.
Reconnect battery.
To prevent damaging the engine electronic systems, install
all ground wire previously removed, including the ground
wires for the ignition coils.
Tightening torque
-
Radiator cooling fan to coolant pump 40 Nm
(30 ft-ib)
Spark plug to cylinder head
25 Nm (18 ft-ib)
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Cylinder Head and Valvetrain
< Disconnect fuel injector electrical connectors from injectors.
Pry corner of wire lock clip (arrow) on first injector.
* Repeat for all injectors.
Lift wiring ducts off and set aside.
4 Remove right and left side ignition coil mounting nuts (ar-
rows) and coils.
NOTE-
Male note of location for ground straps (arrow A).
- Remove spark plugs.
- Disconnect positive (+)jumper junction from top of lefl cylin-
der head cover.
4 Remove retaining nuts (arrows) and remove oil lines from
left and right cylinder heads.